Mechanically-actuated diaphragm horn or alarm.



n M. R.`HUTHISON. MEGHANIGALLY AGTUATED DIAPHRAGM HORN OB. ALARM.

APPLICATION RILBD 00T.14, 190B.

Patented May 25, 1909.

MILLER REESE HUTCHISON,

OF SUMMIT, NEW JERSEY.

MECHANICALLY-ACTUATED DIAPHRAGM HORN OR ALARM.

Original application filed March 14, 1906, Serial No. 305,933.

Serial No.

To all whom it may concern:

Be it known that I, MILLER Rnnsn HUTCHI- SON, a citizen of the United States, and resident of Summit, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Mechanically-Actuated Diaphragm Horns or Alarms, of which the following is a specifi.- cation.

This invention relates to signaling or alarm horns, adapted for use on automobiles, fire engines, launches, steam boats, light houses, factories, etc.

In the form illustrated herein, the device includes a diaphragm, actuating mechanism, and a motor, preferably inclosed in a case provided with a resonator or horn so as to constitute a compact alarm adapted for portable use or use in exposed positions of all kinds.

In my prior application, Serial No. 305,933, filed March 14th, 1900, I have illustrated in Figure 1 a resonator and a case containing the diaphragm and means for mechanically vibrating the diaphragm. In Fig. 2, I have shown an electric motor and a system of circuits adapted to be used in connection with the resonator, diaphragm, and case of Fig. 1. In Fig. 9, I have shown an arrangement wherein the eriphery of the rotary driving members of Wigs. 1 and 2 is formed with a plurality of cam surfaces contacting with a wear piece or thrust member on the diaphragm.

My present application is a division of said prior application, and includes the cam arrangement of Fig. 9, shown as combined with the motor of Fig. 1 and the case and resonator of Fig. 1, after the manner described in said prior application.

According to my present invention, I inclose within the case behind the diaphragm, a small rotary motor having the cam mounted directly on the armature shaft and arranged in operative relation to the diaphragm. The case is adapted to be water and dust tight and the cam is designed with reference to the speed of the motor, so as to force vibration of the dia]fihragm, preferably in a direction perpendicular to its surface. To this end, the cam is preferably of low )itch on the advancing side and contacts with a relatively low thrust member or wear piece on the diaphragm. The motor may be of any desired size and power operated from any desired source of current, but

Specification of Letters Patent.

Patented May 25, 1909.

Divided and. this application filed October 14, 1908. 457,710.

the efficiencies of this method of forcing vibration of the diaphragm is so great that very powerful sounds may be produced where the motor is quite small and consumes but little current. In certain cases it may have an operating voltage so low as to be readily supplied from storage or other batteries used for igniting an explosive motor such as may be used to drive the conveyance, though any suitable source of current may be used as, for instance, a small generator driven from any desired rotating part of the engine. The horn may be controlled by controlling the circuit from any desired point or points.

Referring to the drawings: Fig. 1 is a transverse section of the case looking toward the diaphragm and showing the motor in position in the said case. Fig. 2 is a longitudinal section in a plane parallel with the motor shaft. taken at right angles to the section of Fig. 2.

As will be understood, the invention may be embodied in various specifically different forms, but I prefer to employ a horn 1 and a case 2, though any form of resonant amplifier may be employed or may be omitted, as may also the case 2. These parts of the device may be of any known or desired construction.

As shown in Fig. 1, the horn is screwed into a nipple 3 in an end closing cap or wall screwed to the case 2. The horn is secured by a set screw 3, and the end closure 4 may be provided with any desired locking means. Its front wall is preferably parallel with the diaphragm and close to it.

The vibratory member for exciting the horn may be held in any desired way and may be a diaphragm 5 held by suitable washers 6, and may be clamped between the front ends of the case 2 and the end closing ca a 4.

]The diaphragm is displaced by the cam projection 54, on disk 15, contacting the thrust or wear piece 55. The latter is provided with a reduced extension or stud al, extending through a perforation in the diaphragm and secured by lock nuts 43. Any other suitable securing means 1may be employed. The cam disk is mounted upon the shaft of the rotary motor 30, which may be mounted within a case 2 in any suitable manner.

Circuit leads 31, 32 connect the motor with any suitable source of current as, for in- Fig. 3 is a longitudinal section .is substantially concentric with the axis, so

stance, the battery indicated at 33 and there may be bridged thereacross any desired number of circuit closers 34, the closure, of any of which will serve to start the motor and sound the horn. An adjustable impedance 35, may be included in this circuit and may be either an inductive or an ohmic. resistance or both and may be designed and regulated either to limit the maximum normal operating current or to prevent too sudden and too great instantaneous current at starting or to accomplish both functions.

By reason of the comparatively large amount of power available from the rotary motor and of the advantageous application thereof to the diaphragm through the cam projections, the diaphragm may be of relatively great diameter, stiffness, and amplitude of vibration. lt is preferably mounted for vibration on both sides of normal. lith a diaphragm six inches in diameter, the amplitude of vibration may be 1/32 to 3/32 inch, but it will be understood that these figures are merely illustrative of a particular case. ln practice, wide variations are possible.

By applying power to the vibrating diaphragm mechanically in accordance with my present invention, l am enabled to select the material of such diaphragm with a view solely to securing the elastic qualities and acoustic properties most desirable in such a member without reference to the electromagnetic qualities which must be considered where the power is to be applied magnetically. I may make the diaphragm of any desired diameter and thickness and of any desired quality of elastic material, as, for instance, soft iron, spring steel, wood, etc.

In the form shown herein, the cam projections 54 on disk 55 have their operative faces on the advancing side formed as convex curves of progressively increasing radius. The back side of the projection is cut away so as to present an approximately radial surface. In such an arrangement the convex surfaces on the advancing side progressively force the diaphragm outward and the return movement is entirely elastic.

By reference to the drawing, it will be seen that the periphery between the rear face of one cam projection and the beginning of the convex portion of the next cam projection that the time of elastic return corresponds approximately to the time of the forcing action of the cam and to the rate or velocity imparted thereby to the diaphragm. The cam projections are preferably equally spaced and of equal height, so that the diaphragm movements occur at approximately equal intervals and are of approximately equal amplitude. The rotary cam being mounted on the armature shaft of an electric motor, 1s especially adapted for a wide range j of speeds. lVhen in full operation, the swing of the diaphragm is partly forced and partly free, and the note produced is of a frequency equal to the revolutions per second multiplied by the number of cam projections. The number of cam projections and their distance apart are preferably such that when driven at the desired speed, they will permit of elastic return of the diaphragm through a desired distance before the next cam projection forces the next outward movement. The rates or frequencies of the movements forced on the diaphragm by the cams may be practically independent of the natural frequencies of free vibration of the diaphragm. Great resonant sound effect with small expenditure of power will be attained, however, when the forced movement and the natural movement is of the same frequency. This may be accomplished even for very high frequencies by multiplying the number of cams 54 and preferably correspondingly increasing the periphery of the disk l5, so as to maintain spacing of the cam projections.

With any given number of cam projections arranged on any given periphery, the frequency may be increased by speeding up the revolutions of the cam shaft. ln no case, however, can single acting cams, such as herein shown, operate to increase the frequency beyond a certain limit dependent upon the elasticity and inertia of the diaphragm. The coupling of the driver and driven member being loose, the rate of positive outward displacement of the diaphragm is necessarily limited by the time required for the elasticity of the diaphragm to bring it back within range of the cam projection. There the cam contacts occur more frequently than the natural period of elastic vibration of the diaphragm, the amplitude of the movement will be cut short. Hence, the times and velocities of the cani forcing movements in one direction are preferably harmonized with the times and velocities of the elastic return movements, although abrupt or radial faces on the back side of the cam projections will always permit high velocity elastic return of the diaphragm no matter how slow may be the outward movement forced by the front side of the cam.

ln all of the above cases of partly forced and partly free movements, if a horn or resonator is used having a pronounced natural frequency, the natural vibratory movements of the diaphragm will tend to harmonize with the natural frequencies of the horn so that within limits the natural Vfrel l quencles of the diaphragm become the same as the natural Vfrequency of the horn. This is of particular value in connection with an electric motor drive where the speed is free to vary proportionally to the work done, since with such motive power, the displacement tends to set itself in synchronism. or harmony with one of the natural resonant frequencies of the device, so that in turning on or turning off the motive power, the note tends to dwell at one natural frequency until the power increases to a point Where it can jump to the next natural frequency.

It will be understood that the thrust or displacement of the diaphragm is a function of the shape and. arrangement of both the driving and the driven member and that in the drawings the cam action results from den velopment of the cam surfaces on both members. Obviously, the proportion of the cam thrust afforded by each is capable of Wide variation between the extremes Where all of the cam thrust or displacement is afforded by one member or by the other member.

While I have herein above set forth certain desirable principles of proportioning of parts and rates of operation thereof, it Will be understood that many of the structural features of my present invention do not depend upon such special matters. It Will also be understood that While I have herein fully shown and described., and have pointed out in the appended claims certain novel features of construction, arrangement, and op eration which characterize my invention, it will be understood by those skilled in the art that various omissions, substitutions, and changes in the forms, proportions, sizes, and details of the device and of its operation, may be made without departing from the spirit of my invention.

The rotary electric motor energized from storage batteries as herein shown, is peculiarly adapted for use With the type of cam designed for operation in one direction of rotation only, because the shunt Winding of the field commonly employed for such motors, insures a proper direction of rotation for the cam, regardless of the direction of the supply current. Hence, the motor and cam may be completely inclosed in a tight case and the device connected up Without the necessity of any attention to the matter of polarity of the source.

l claim:

1. ln a signaling apparatus of the class described, a Isuitable case and a resonator secured to said case, in combination with a diaphragm, rotary motor, and a cam located for positively vibrating said diaphragm, all inclosed Within said case, for the purpose described.

2. In a signaling apparatus of the class described, a suitable case and a resonator secured to said case, in combination with a diaphragm, a rotary electric motor, and a rotary cam mounted upon the armature shaft of said motor and positively displacing said diaphragm, said parts being inclosed within said case, for the purpose described.

3. In a signaling apparatus of the class described, a suitable case and a resonator secured to said case in combination with a diaphragm, a rotary electric motor, and mechanical forcing means positively applying the power of said motor to vibrate said diaphragm, said parts being inclosed Within said case, for the purpose described.

4. In an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of different pitch in the other direction of rotation, in combination with driving means for said cam, arranged or connected so as to rotate said cam in one selected direction only.

5. ln an alarm or signaling apparatus of the class described, a diaphragm, a projech tion on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of different pitch in the other direction of rotation, in combination with an electric direct current rotary motor for said cam, arranged or connected so as to rotate said cam in one selected direction only, for the purpose described.

6. In an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of different pitch in the other direction of rotation, in combination With an electric motor having its armature on the same shaft with said cam, said motor being arranged or connected so as to rotate said cam in one selected direction only, for the purpose described.

7. In an alarm or signaling apparatus ol the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with driving means for said cam arranged and connected so as to rotate said cam in the former direction only, for the purpose described.

8. ln an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotaryr camv in operative relation to said projection, said parts being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation in combination With an electricl direct current rotary motor for said cam arranged and connected so as to rotate said cam in the former direction only, for the purpose described.

9. In an alarm or signaling` apparatus ot the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being formed and arranged lor operation in one direction of rotation of said cam rather than in the other direction ol rotation, in combination with an electric motor having its armature on the saine shalt with said cam, said motor being arranged and connected so as to rotate said cam in the former direction only.

10. In an alarm or signaling apparatus oll the class described, a diaphragm, a projection on said diaphragi'n, and a rotary cam in operative relation to said projection, said projection being designed and arranged to have an operative cam action ol' given pitch in one direction ol' rotation and having a diiierent pitch in the other direction ol' rotation, in combination with driving means lor said cam, arranged or connected so as to rotate said cam in one selected direction only, for the purpose described.

11. In an alarm or signaling apparatus ol the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said projection being formed and arranged l'or operation in one direction oi' rotation ol' said cani rather than in the other direction of rotation, in combination with driving means for said cam arranged and connected so as to rotate said cam in the i'ormer direction only, for the purpose described.

12. In an alarm or signaling apparatus oll l the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said projection being formed and arranged lor operation in one direction ol rotation of said cam rather than in the other direction of rotation, in combination with an electric direct current rotary motor l'or said cam arranged and connected so as to rotate said cam in the former direction only, for the purpose described.

13. In an alarm or signaling apparatus of the class described, a diaphragm and a rotary cam in operative relation to said diaphragm, said rotary cam having cam faces suitably designed lor operation in one direction of rotation, in combination with' connected so as to rotate said cam in the iirst mentioned direction only, l'or the purpose described.

15. In an alarm or signaling apparatus oll the class described, a diaphragm and a rotary cam in operative relation to said diaphragm, said cam having its operative faces on the sides presented in one direction of rotation l'ormed on convex curves and having its rear l'aces abrupt, in combination with driving means 'l'or said cam arranged and connected so as to rotate said cam in the first mentioned direction only, i'or the purpose described.

16. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a high speed rotary motor and a rotary cam for vibrating said diaphragm, mounted upon a high speed shaft driven from said motor, said cam having its periphery formed with approximateljT similar cam projections of gradualljT increasing radius on the sides presented in one direction of rotation, and, alternating therewith, cam depressions o'l peripheral extent approximately equal to the peripheral extent ol' said sur- Yl'aces ol gradually increasing radius, for the 5T purpose described.

17 In an alarm or signaling apparatus oi' the class described, a diaphragm in combination with an electric direct current rotary motor and a rotary cam for vibrating said i diaphragm mounted on the armature shalt oi' said motor, said cam having its periphery formed with approximately similar cam proj ections of gradually increasing radius on the sides presented in one direction ol` rotation, and, alternating therewith, cam depressions ol' circumferential extent approximately equal to the peripheral extent of said surfaces ol gradually increasing radius, for the purpose described.

18. In an alarm or signaling apparatus of the class described, a diaphragm in combination with an electric direct current rotary motor and a rotary cam tor vibrating said diaphragm mounted on the armature shaft of said motor, said cam having its periphery formed with approximately similar cam projections of gradually increasing radius on the sides presented in one direction 0l' rotation, and, alternating therewith, cam depressions of circumferential extent approximately equal to the peripheral extent of said surfaces o'll gradually increasing radius; all of said parts being securedly inclosed within a suitable case and operatively associated with a horn or resonator secured to said case; t0- gether with means extending outside oll said case for controlling the operation oil said motor, for the purpose described.

19. In an alarm or signaling apparatus of ill) lll)

the class described, a diaphragm, in combination with a rotary cam for vibrating said diaphragm, said cam having its periphery formed With approximately similar cam proe jections of gradually increasing radius on the sides presented in one direction of rotation and alternating therewith cam depressions of peripheral extent approximately equal to the peripheral extent of said surfaces of gradually increasing radius, for the purpose described.

20. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a rotary cam for vibrating said diaphragm, said cam having its operative cam faces on the advancing side of small radial eccentricity or altitude as compared with their peripheral extent and having its rear faces abrupt, for the purpose described.

21. In an alarm or signaling apparatus of the class described, a diaphragm, in combination With a rotary cam adapted to forcibly displace said diaphragm, said cam having its operative faces on the advancing side formed on convex curves and having its rear faces abrupt, for the purpose described.

22. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam positively displacing said diaphragm, said cam having its operative faces on the advancing side formed on convex curves, for the purpose described.

23. In an alarm or signaling apparatus of the class described, a diaphragm, in combination With a rotary cam adapted to forcibly displace said diaphragm, said cam having its operative cam faces on the advancing side formed on convex curves having small radial eccentricity or altitude as compared With their peripheral extent and having its rear face of small peripheral extent as compared with the peripheral extent of said operative cam faces, for the purpose described.

24. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam for vibrating said diaphragm, said cam having a plurality of similar cam projections, said projections being of low pitch on the side presented in one direction of rotation and of steep pitch on the sides presented in the other direction, for the purpose described.

25. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam positively displacing said diaphragm, said cam having its operative cam faces on the advancing side formed on convex curves having small radial eccentricity or altitude as compared With their peripheral extent, for the purpose described.

26. In an alarm or signaling apparatus of the class described, and in combination, a suitable case, a horn or resonator secured to said case, and, inclosed Within said case, a

diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of dierent pitch in the other direction. of rotation, together with driving means for said cam, arranged or connected so as to rotate said cam in one selected direction only, for the purpose described.

27. In an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of different pitch in the other direction of rotation, in combination with an electric direct current rotary motor for said cam, arranged or connected so as to rotate said cam in one selected direction only all of said parts being securely inclosed Within a suitable case and operatively associated with a horn or resonator secured to said case; together with means extending outside said case for controlling the operation of said motor, Yfor the purpose described.

28. In an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being designed and arranged to have an operative cam action of given pitch in one direction of rotation and being of different pitch in the other direction of rotation, in combination with an electric motor having its armature on the same shaft With said cam, said motor being arranged or connected so as to rotate said cam in one selected direction only; all of said parts being securely inclosed Within a suitable case and operatively associated with a horn or resonator secured to said case; together With means extending outside said case for controlling the operation of said motor, for the purpose described.

29. In an alarm or signaling apparatus of the class described, a suitable inclosing case containing a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with driving means for said cam arranged Within said case and connected so as to rotate said cam in the former direction only, for the purpose described.

30. In an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said parts being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with an electric direct current rotary motor 'for said cam arranged and connected so as to rotate said cam in the former direction only; all of said parts being securely inclosed Within a suitable case and operatively associated with a horn or resonator secured tosaid case; together with ineans extending outside said case for controlling the operation of said motor, for the purpose described.

3l. 1n an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cani in operative relation to said projection, said parts being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with an electric motor having its armature on the same shaft with said cam, said motor being arranged and connected so as to rotate said cam in the former direction only; all of said parts being securely inclosed within a suitable case and operatively associated With a horn or resonator secured to said case; together with means extending outside of said case for controlling the operation of said motor, for the purpose described.

32. 1n an alarm or signaling apparatus of the class described, a suitable inclosing case containing a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said projection being designed and arranged to have an operative cam action of given pitch in one direction of rotation and having different pitch in the other direction of rotation, in combination with driving means for said cam, arranged Within said case and connected so as to rotate said cam in one selected direction only, for the purpose described.

33. 1n an alarm or signaling apparatus of the class described, a suitable inclosing case containing a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said projection being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with driving means for said cam arranged Within said case and connected so as to rotate said cam in the former direction only, for the purpose described.

34. 1n an alarm or signaling apparatus of the class described, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said projection being formed and arranged for operation in one direction of rotation of said cam rather than in the other direction of rotation, in combination with an electric direct current rotary motor for said cam arranged and connected so as to rotate said cam in the former direction only all of said parts being securedly inclosed Within a suitable case and operatively associated with a horn or resonator secured to said case, together with means extending outside of said case for controlling the operation of said motor, for the purpose described.

35. In an alarm or signalingl apparatus of the class described, a suitable inclosing case containing a diaphragm and a rotary cam for vibrating said diaphragm, said rotary cam having projections formed with cam surfaces of low pitch on the sides presented in one direction of rotation only, in combination with driving means for said cam arranged within said case and connected so as to rotate said cam in the above mentioned direction only, for the purpose described,

36. In an alarm or signalingl apparatus of the class described, a suitable inclosing case containing a diaphragm and a rotary cam for vibrating said diaphragm, said rotary cam having projections formed with cam surfaces of loiv pitch on the side presented in one direction of rotation and having abrupt surfaces on the sides presented in the other direction of rotation, in combination with an electric direct current rotary motor for driving said cam arranged within said case and connected so as to rotate said cam in the i'irst mentioned direction only, for the purpose described.

37. In an alarm or signaling apparatus of the class described, a diaphragm and a rotary cam for vibrating said diaphragm, said rotary cam having projections formed with cam surfaces of low pitch on the sides presented in one direction of rotation and surfaces of steeper pitch on the sides presented in the other direction of rotation, in combination with an electric motor for driving said cani arranged and connected so as to rotate said cam in the first mentioned direction only; all of said parts being` securely inclosed within a suitable case and operatively associated with a. horn or resonator secured to said case, together with means extending outside of said case for controlling the operation of said motor, for the purpose described.

38. 1n an alarm or signaling apparatus of the class described, a diaphragm and a rotary cam in operative relation to said diaphragm, said cam being formed with its operative cam faces on the sides presented in one direction of rotation of small radial eccentricity or altitude as compared with their peripheral extent, and having the rear faces presented in the other direction of rotation of small peripheral extent as compared With the peripheral extent of said first mentioned faces, in combination with a motor for driving said cam arranged and connected so as to rotate said cam in the first mentioned direction only; all of said parts being securely inclosed Within a suitable case and operatively associated with a horn or resonator secured to said case, together With www means extending outside of said case ior controlling the operation oi" said motor, for the purpose described.

39. In an alarm or signaling apparatus of' the class described and in combination, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said diaphragm projection having a cam surface of relatively low pitch in one direction of engagement and having less pitch in the other direction of engagement, for the purpose described.

40. In an alarm or signaling apparatus of the class described and in combination, a

diaphragm, a projection on said diaphragm,

and a rotary cam in operative relation to said projection, said diaphragm projection having a broad engaging face presented in one direction of rotation ol said cam and an abrupt face presented in the other direction, for the purpose described.

41. In an alarm or signaling apparatus of the class described and in combination, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said diaphragm projection having its engaging face inclined in one direction only, for the purpose described.

42. In an alarm or signaling apparatus of the class described and in combination, a diaphragm, a projection on said diaphragm, and a rotary cam in operative relation to said projection, said diaphragm projection and said cam both having cam surfaces of low pitch on the engaging sides and both terminating in abrupt surfaces on the rear sides, for the urpose described.

43. In an a arm or signaling apparatus of the class described and in combination, a diaphragm, a projection on said diaphragm, and a rotary displacing member in operative relation to said projection, said diaphragm projection having a cam surface of relatively low pitch in one direction of engagement and having a steep pitch in the other direction of engagement, for the purpose described.

44. In an alarm or signaling apparatus of the class described and in combination, a diaphragm, a projection on said diaphragm, and a rotary displacing member in operative relation to said projection, said diaphragm projection having a broad engaging face inclined in one direction only and presenting an abrupt face in the other direction, for the purpose described.

45. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam positively displacing said diaphragm, said rotary cam being formed with a plurality of cam projections, proportioned and arranged so as "to have their operative cam throw in a direction perpendicular to the diaphragm small as compared with the distance between their summits, for the purpose described.

46. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam adapted. to forcibly displace said diaphragm, said rotary cam being formed with a plurality of spaced cam projections, proportioned and arranged so as to have their operative cam throw in a direction perpendicular to the diaphragm small as compared with the distance between their summits whereby clearance is given during rotation, together with means for rotating said cam at a peripheral velocity much greater than the transverse velocity of free elastic vibration of said diaphragm, for the purpose described.

47. In an alarm or signaling apparatus ol the class described, a diaphragm, in combination with a rotary cam positively vibrating said diaphragm, said rotary cam being formed with a plurality ol' spaced cam projections, proportioned and arranged so that their operative cam i'aces are oi' small altitude as compared with the distance between their summits whereby clearance is given during rotation, together with means for rotating said cam at a speed harmonizing with the elasticity of the diaphragm, for the purpose described.

48. In an alarm or signaling apparatus of the class described, a diaphragm, in combination with a rotary cam provided with a plurality oiI spaced cam projections positively vibrating said diaphragm and means Yfor driving said cam at a desired peripheral velocity, the altitude of said projections, the space between them, and the peripheral speed imparted by the driving means being proportioned to positively force diaphragm vibrations ci the required velocity, amplitude, and frequency, for the purpose described.

49. In a signaling apparatus oi the class described, a suitable case and a horn or resonator secured to said case, in combination with a diaphragm, a rotary electric motor,

arranged with its armature shaft approximately parallel with said diaphragm, and means mechanically and positively applying the power oll said motor shai't to 'forcibly vibrate said diaphragm, all inclosed within said case, together with external operating means, for the purpose described.

50. In a signaling apparatus of the class described, a suitable case and a horn or resonator secured to said case, in combination with a diaphragm, a rotary electric motor, arranged with its armature shaft approximately parallel with said diaphragm, and a rotary cam mounted upon the armature shaft ol said motor and positively displacing said diaphragm, for the purpose described.

5l. In an alarm or signaling apparatus oi the class described, a diaphragm and a horn or resonator o'i definite resonant frequencies associated therewith, in combination with a rotary driving member positively vibrating said diaphragm at all spceds and a direct current electric motor l'or driving said rotary member at high speeds, including a speed sufiicient to produce a note ol' the same. Vl'requency as one ol' said resonant frequencies,

substantially as and l'or the purpose de-ii scribed.

52. In an alarm or signaling apparatus ol' the class described, a suitable case, a horn or resonator secured to said case, and, inclosed Within said case, a diaphragm and a rotary driving member positively vibrating said diaphragm, arranged to operate 1n one direction only, and a direct current electric motor mechanically connected to drive said rotary member' in the proper direction only, in combination with an external source ol' l i l l l l i 1 direct current and means for connecting said source With said motor, as and 'for the purpose described.

53. lu a signaling apparatus o' the class described, a suitable oase and a horn or resonator secured to said case, in combination with a diaphragm, a rotary electric motor,

and a rotary cam mounted upon the arma- 

